1. Field of the Invention
The present invention relates to semiconductor package and method of making the same.
2. Description of the Related Art
In recent semiconductor packages, a lead frame is replaced by a printed circuit board, so as to lower the inductance and greatly improve electric capability, heat discharging capability and surface mounting capability of the semiconductor package.
In such a semiconductor package, a semiconductor die is mounted on a printed circuit board by using an adhesive, die pads are in turn wire-bonded to bond fingers of the printed circuit board by conductive wires, and then the semiconductor die is encapsulated by using an Epoxy Molding Compound (EMC).
On the other hand, as the weight and size of small sized and portable electric/electronic devices, such as cellular phone, digital video camcorders, digital cameras, lap-top computers, etc., gradually reduces more and more, it is necessary to also reduce the weight and size of semiconductor packages mounted in the electric/electronic devices. This requirement has caused appearance of ultra-small sized semiconductor packages such as chip size package and wafer level chip size package.
The encapsulation of the semiconductor die is performed by a transfer molding in which melted EMC is injected into a mold. In the semiconductor package, it is typical to secure a distance of at least 10 mil between a surface of the semiconductor die and a surface of molded semiconductor package in order to avoid occurrence of voids in the semiconductor package as well as to prevent incomplete molding of the semiconductor package. However, such a transfer molding using the EMC may cause big limit in realization of ultra-small or ultra-slim semiconductor packages, which is a recently popular trend.
Further, in the transfer molding using the EMC, the EMC is injected into the semiconductor package from one side of the semiconductor die, which may cause a wire sweeping phenomenon in which conductive wires are gathered on one side of the semiconductor package.
Moreover, the wire sweeping may separate the bonded conductive wires from the bond pads of the semiconductor die or the bond fingers of the printed circuit board, thereby causing disconnection of the conductive wires and electrical interconnection of the conductive wires, which may induce the electrical short-circuit.
Furthermore, according to the transfer molding manner using EMC, the completed semiconductor package only comes in a black color. Therefore, the semiconductor package fails to satisfy a consumer expectation of various colored semiconductor packages, thereby reducing a consumer's purchasing desire.